So I bought an old GP14

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PoppyT
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So I bought an old GP14

Post by PoppyT » Sun Aug 07, 2016 10:04 am

And that's about all I know about it! Complete newbee to this and a good ten years since I did any sailing at all.
So I'm renovating this 14, repairs done save the centre 'webbing' across the centre board. It's perished and needs replacing but I cannot remove the brass screws in the securing pate. Have got rid of all the paint in the screw head but they'll not budge. Any ideas??
Many thanks

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trebor
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Re: So I bought an old GP14

Post by trebor » Sun Aug 07, 2016 10:49 am

Brass screws, screw driver always needs to be a good fit, lots of weight on screw driver.
When they have gone, I usually drill out, start off with a small drill bit, down length of screw, then a larger one, do this until you have removed screw, head will just lift away once shaft's gone.
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Rupert
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Re: So I bought an old GP14

Post by Rupert » Sun Aug 07, 2016 9:59 pm

There are devices to drill out round them. Brain not remembering what they are called right now!
Rupert

PoppyT
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Re: So I bought an old GP14

Post by PoppyT » Mon Aug 08, 2016 10:10 am

Thanks! Will give it a go...

chris
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Re: So I bought an old GP14

Post by chris » Mon Aug 08, 2016 1:04 pm

If they are still reasonable sound then a good bit of light tapping with a hammer on the end of a well-fitting screwdriver can often help to wake them up. Then don't try and turn them in one go but nudge the screwdriver a small but firm bit at a time - even backwards and forwards can work them free.
If they are well corrode the head will probably break off!

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TheGuvnah
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Re: So I bought an old GP14

Post by TheGuvnah » Mon Aug 08, 2016 9:10 pm

Clearing the slot of paint is the first step but in circumstances like this I would also go round the outside of the head and remove any paint covering that timber/metal interface. I get in there with an engineer's scribe to get right into the countersinks and get every last bit. Then I'd apply a 25/35watt soldering iron to introduce some controlled heat into proceedings. It fractionally expands the screw and helps break the threads free of its encrustation. Brass/bronze are excellent heat conductors so it travels the length of the fixing nice and quickly. Let it cool then do it again. The first turn of the (close fitting) driver should be in a tightening direction and then you can reverse it to extract. As Chris said, work it forwards/backwards. If you haven't got a screwdriver that fits EXACTLY don't be afraid to sacrifice a cheap pound shop jobby by filing and stoning the tip of it down until it IS an EXACT fit in the FULL DEPTH of the slot. In fact I like to have the tip a few thou too wide such that it requires a light thud with your palm or hammer to seat in fully home into the slot. Ideally it'll stand in the slot without you needing to hold it! Then you know it's tightly seated. Any wobble is an invitation to graunch the slot.
This is when I apply the taps with a small knock-ometer as mentioned which are usually effective in cracking the 'sticktion' by imitating the action of an impact driver but there's a limit to how much torque a brass screw will ultimately take so the chances of shearing a few off are high and just goes with the territory really.

Should the worst happen and the head shears clean off one method of extracting the remains of the threaded part is to find a bit of steel tube which will just clear the shank of the screw (bit of steel brake pipe perhaps?) and file a few saw teeth around one end. Give it a quick harden and temper with a MAPP gas blowtorch (optional) and it's good to go. Stick it in the drill and it will core around the shank. I heard it suggested that you can cut the 'teeth' in a reverse direction and switch the drill to reverse. I have read that it will often get a grip pf the screw halfway in and start to grip the shaft and wind it out. you might also try using one of those spring steel 'roll pins'. If the internal diameter is a close grip fit over the screw shank then again you can try filing the end flat and then introduce a single tooth cutting edge on ithe leading edge of its slot (Dremel + mini grinding disc is the tool for this, roll pins are pretty hard) such that it will cut with the drill in reverse. Start cutting and the heat generated by the cutting and the friction of the roll pin on the screw shank will help free up the fastener and the idea is that the roll pin will 'catch' on the shank at some point and start to draw out the screw
Of course it'll leave a hole to be plugged but that will be a lot easier to make good than the potential butchery that can result from trying to end drill a screw freehand with a battery driller. Sheared screws always leave a point which will cause any drill bit to immediately wander and slide off into your precious timberwork, even centre punching the stump won't always prevent the drill from 'walking' but it might be worth trying to use a Dremel with a 3mm carbide burr on the sheared end in order to create a concave recess to give the bit an easy self-centering lead in.

I'm pretty good with a drill but I'd be cautious about end drilling small screws in intimate contact with precious timbers. One slip and ... aaaargh!!!

Here's a thought. If you have one of those small 'domestic' drill presses and the screw's location allows access you could try swinging the drill clear of the base, centre it over the screw in question and fix in place with G cramps/wedges/temporary base board or however, put a screw driver bit in the drill's chuck, bring the chuck down onto the screw and the pressure of you leaning on the handle keeps the blade in the slot whilst you apply the turning force with a bit of 1/4" rod in one of the chuck's 3 tightening holes.
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TheGuvnah
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Re: So I bought an old GP14

Post by TheGuvnah » Mon Aug 08, 2016 10:53 pm

Oh hang on... here you go...

viewtopic.php?f=23&t=6160
...well if it was easy everybody would have one.

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